The present invention relates generally to rotatable impact sprinklers and more particularly to a rotatable impact sprinkler having a partial circle distribution pattern and a water deflector which minimizes sprinkler backsplash and at the same time minimizes flooding at and around the sprinkler itself.
Rotating sprinklers of the impact type are well known in the art. A typical sprinkler of this type includes a sprinkler body having a jet nozzle, an oscillating arm and a water deflector mounted to one end of the arm for movement into and out of a jet of water issuing from the nozzle. The oscillating arm is spring biased against the body of the sprinkler with the deflector in the path of the jet stream of water issuing from the nozzle. In operation, water issuing from the nozzle impinges upon the deflector causing the deflector to move out of the jet and causing the oscillating arm to move out of its biased position. With the deflector out of the jet, the oscillating arm moves back to its biased position and forcibly engages the sprinkler body causing it to rotate an increment. This procedure is then repeated to provide the desired amount of sprinkler rotation.
One drawback with an impulse type rotational sprinkler of the type just described resides in the "backsplash" resulting from the manner in which this type of sprinkler operates. More specifically, much of the water issuing from the jet nozzle and impinging on the deflector is deflected back to one side of the nozzle thereby creating a backsplash. Considering that the deflector typically oscillates into and out of the jet stream at a relatively high rate, for example, 150 times per minute, this backsplash can produce a relatively large amount of water during operation of the sprinkler. Where the particular sprinkler is a full circle sprinkler this backsplash is of no consequence except that the backsplash water could flood around the sprinkler head. Where the sprinkler is one which provides partial circle service, for example, where the sprinkler is located adjacent a walk, a building, or a street, the backsplash may be highly objectionable in that a large amount of water through the course of the sprinkler operation is ultimately directed onto the walk, building or street.
This backsplash drawback has been dealt with and to a large extent minimized by a sprinkler disclosed in U.S. Letters Pat. No. 3,022,012 which is issued on Feb. 20, 1962, to C. R. Sharp and John E. Streeter. This sprinkler as disclosed in the Sharp et al patent utilizes what is referred to as an S-shape reaction member or tube for intermittently deflecting water issuing from the sprinkler nozzle. The reaction tube is permanently fixed to the arm of an oscillating lever also comprising part of the sprinkler such that one end of the reaction tube, specifically the inlet end, is in alignment with the water jet issuing from the nozzle when the oscillating lever is in one extreme position. An intermediate portion of the reaction tube extends laterally at an obtuse angle with the inlet end and the other end of the tube, specifically the discharge end, is offset from but in approximate parallelism with the inlet end.
In operation, the reaction tube disclosed in the Sharp et al patent initially comes into registry with the water jet issuing from the sprinkler nozzle causing water to enter the inlet end of the reaction tube. Before an appreciable flow occurs through the reaction tube, there occurs a momentary force component tending to rotate the reaction tube further into the water jet thereby drawing the tube into its ultimate position in alignment with the sprinkler nozzle. Additional forces are established as a result of the flow of the water jet through the tube, these forces acting to move the tube back out of the path of the water jet, i.e., to one side of the sprinkler nozzle.
In accordance with the disclosure in the Sharp et al patent and from observing the operation of an actual sprinkler constructed in accordance with the Sharp et al patent, there is an increase in the turbulence of the water as it passes through the reaction tube. As used herein and obviously as used in the Sharp et al patent the term "turbulence" refers to a relatively unsmooth flow of water as opposed to a smooth or sheet-like flow. Applicant has found this increase in turbulence to be objectionable for a number of reasons. First, Applicant has found that an increase in turbulence in the reaction tube results in increased flooding of water around and in close proximity to the sprinkler itself, for example within about two feet from the sprinkler. More specifically, much of the water in the tube which is subjected to turbulence does not reach what may be referred to as the intermediate range in the overall water distribution pattern but rather falls substantially short of this intermediate range creating a flood around the sprinkler. This results in a second drawback which is that the intermediate range of the overall pattern which normally receives deflected water does not receive as much water as it otherwise would since much of the deflected water is deflected around the head of the sprinkler. In other words, Applicant has found that the turbulence in the reaction tube produces more water than is desirable around the head of the sprinkler and less water than is desirable in the intermediate range of the pattern. The outer range of the pattern is, of course, for the most part unaffected by this situation since the outer range receives most of its water from the undeflected jet of water issuing from the sprinkler nozzle.
As will be seen hereinafter, the present invention provides a substantial improvement to the sprinkler just described. Briefly, this improvement resides in minimizing substantially if not eliminating the turbulence within the water deflector without adversely affecting the production of required torque forces to produce efficient oscillation of the deflector and oscillating arm. Moreover, the uniformity of the overall distribution pattern has been improved in that much of the water which has heretofore flooded around the sprinkler head is directed further out into the intermediate range of the pattern.